Air pollution has become a major problem, and many devices for cleaning, or purifying exhaust air have heretofore been suggested and/or utilized. While such devices have been suggested and/or utilized, for example, to remove particulate matter from the exhaust emitted by an internal combustion engine and from smoke stacks and the like of industrial plants, such devices have met only limited success, have been unduly complicated and expensive for general use, have not been adapted for replacement of filter sections while retaining intact other portions of the device, have required reconstruction of the combustion system to accomodate the air cleaning device, and/or have imposed undue restrictions on the combustion system so as to make the combustion system virtually inoperable in its intended manner.